A new approach to analyzing solar coronal spectra and updated collisional ionization equilibrium calculations. ii. updated ionization rate coefficients
In this article, a collisional ionization equilibrium (CIE) was calculated using state-of-the-art electron-ion recombination data for all elements from H through Zn and, additionally, Al-through Ar-like ions of Fe.
Abstract:
We have re-analyzed Solar Ultraviolet Measurement of Emitted Radiation (SUMER) observations of a parcel of coronal gas using new collisional ionization equilibrium (CIE) calculations These improved CIE fractional abundances were calculated using state-of-the-art electron–ion recombination data for K-shell, L-shell, Na-like, and Mg-like ions of all elements from H through Zn and, additionally, Al- through Ar-like ions of Fe They also incorporate the latest recommended electron impact ionization data for all ions of H through Zn Improved CIE calculations based on these recombination and ionization data are presented here We have also developed a new systematic method for determining the average emission measure (EM) and electron temperature (Te )o f an isothermal plasma With our new CIE data and a new approach for determining average EM and Te ,w e have re-analyzed SUMER observations of the solar corona We have compared our results with those of previous studies and found some significant differences for the derived EM and Te We have also calculated the enhancement of coronal elemental abundances compared to their photospheric abundances, using the SUMER observations themselves to determine the abundance enhancement factor for each of the emitting elements Our observationally derived first ionization potential factors are in reasonable agreement with the theoretical model of Laming
TL;DR: The CHIANTI database as mentioned in this paper provides a set of atomic data for the interpretation of astrophysical spectra emitted by collisionally dominated, high temperature, optically thin sources.
TL;DR: AtomDB 2.0.2 as discussed by the authors is a database of atomic data and a plasma modeling code with a focus on X-ray astronomy, including new ionization balance data, state-selective recombination data, and updated collisional excitation data for many ions, including the iron L-shell ions from Fe+16 to Fe+23 and all of the hydrogen- and helium-like sequences.
TL;DR: AtomDB 2.0.2 as mentioned in this paper is a database of atomic data and a plasma modeling code with a focus on X-ray astronomy, which includes several major updates to the fundamental atomic structure and process data held within AtomDB, incorporating new ionization balance data, state-selective recombination data, and updated collisional excitation data for many ions.
TL;DR: In this article, the first ionization potential (FIP) effect was observed in the solar corona and slow-speed wind, and in the coronae of solar-like dwarf stars, and the "inverse FIP" effect seen in the corona of stars of later spectral type; specifically M dwarfs.
TL;DR: In this article, a review of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind is presented.
TL;DR: In this article, a theory for FIP fractionation is developed which depends on the wave heating of minor ions which extends below the transition region, which is natural on the closed field configurations of large coronal loops but not in the open configurations associated with fields emanating from coronal holes.
TL;DR: In this article, Mazzotta et al. made use of state-of-the-art calculations of dielectronic recombination (DR) rate coefficients for the hydrogenic through Na-like ions of all elements from He up to and including Zn.
TL;DR: In this paper, a one-dimensional temperature and density model is constructed from the analysis of the solar EUV spectrum, which is used to derive the emission measures and the chemical abundances for a number of elements.
TL;DR: In this article, the authors determined the physical properties of the Sun's equatorial west limb streamer region from extreme-ultraviolet (EUV) spectra recorded by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory (SOHO) spacecraft.
TL;DR: In this paper, the average coronal hole and quiet-sun spectra taken during the Skylab mission by Vernazza and Reeves (1978) were used to discuss the energy balance in each region.
Q1. What are the contributions mentioned in the paper "A new approach to analyzing solar coronal spectra and updated collisional ionization equilibrium calculations. ii. updated ionization rate coefficients" ?
The authors have re-analyzed Solar Ultraviolet Measurement of Emitted Radiation ( SUMER ) observations of a parcel of coronal gas using new collisional ionization equilibrium ( CIE ) calculations. With their new CIE data and a new approach for determining average EM and Te, the authors have re-analyzed SUMER observations of the solar corona. The authors have compared their results with those of previous studies and found some significant differences for the derived EM and Te. Their observationally derived first ionization potential factors are in reasonable agreement with the theoretical model of Laming.
Q2. What is the effect of the Alfvén waves on the chromosphere?
These Alfvén waves drive a pondermotive force on their reflection or transmission at the chromosphere–corona boundary which results in the elemental fractionation.
Q3. What is the powerful tool for understanding the properties of the solar corona?
One of the most powerful tools for understanding the properties of the solar corona is spectroscopy (Tandberg-Hanssen & Emslie 1988; Foukal 2004).
Q4. What is the contribution function of emission from Li-like lines?
These authors found that the contribution function of emission from Li-like lines only becomes significantly affected on reaching densities 1011 cm−3, orders of magnitude higher than the density of 1.8 × 108 cm−3 inferred by Feldman et al. (1999) for the observation analyzed here.
Q5. Why is there no common intersection of all EM curves at a single?
Due to oversimplifications of the plasma model, uncertainties in the observations, and errors in the atomic data, there is no common intersection of all EM curves at a single [Tc, EMc].
Q6. What does the fieldman et al. (1998) use to determine the FIP factors?
Feldman et al. (1998), however, use only one or two emission lines to determine the FIP factors for each of the elements they consider.
Q7. What is the EM curve for each of the observed spectral lines?
Using the method described in Section 3, the assumption of constant temperature and density, and their updated CIE results, the authors can calculate the EM curve for each of the observed spectral lines listed in Table 1.